Merge conflict detection compared bigserial (DBML) against bigint (live
PostgreSQL read of an existing serial column) as incompatible types, since
serial is sugar over an integer column plus a sequence default and
PostgreSQL always reports back the underlying integer type. Add
SerialUnderlyingType and use it when comparing column types for conflicts.
QuoteDefaultValue also wrapped bare keyword expressions like CURRENT_DATE
in string quotes because they contain no parentheses, unlike function-call
defaults such as now(). Recognize known bare keyword defaults and leave
them unquoted across CREATE TABLE, ALTER TABLE ADD COLUMN, and
ALTER COLUMN SET DEFAULT generation.
Hein